Scaffold jack



2, 1961 c. F. DlMMlTT 2,997,268

SCAFFOLD JACK Filed Nov. 5, 1959 INVEN TOR /xdr/sr E 0/3/0717? ATTORNEY Un e Sees Filed Nov. 5, 1959, Ser. No. 851,152 4 Claims. (Cl. 248-235) The present invention relates to a scafiold jack adapted to be supported from a parallel pair of vertical studs of a frame structure.

In erecting frame structures, such as houses, it is often necessary to provide scaffolds along the exterior walls for the convenience of the workmen. Such scaffolds are often specially constructed on the site of each job, using earth as a foundation, but this procedure is both time consuming and expensive.

Various arrangements have also been devised for supporting the scaffolding from the wall of the structure itself. Support apparatus of this type is generally disassembled after use and then moved to another job location.

The apparent advantage of the re-usable support apparatus has in fact been illusory, however, so far as prior devices of this type have been concerned. Many difliculties have arisen, primarily from the safety standpoint. If the scaffold support apparatus has been capable of adequately supporting the scaffold, then it has imposed an excessive load on the frame of the structure, with resultant damaging or breaking of the studs. On the other hand, if the support apparatus has been designed in such a way as not to impose an excessive load on the wall of the structure, then it has proven inadequate to provide safe and reliable support for the scaifold.

One object of the invention, therefore, is to provide re-usable scaffold support means which is safe and reliable.

Another object of the invention is to provide a scaffold jack adapted to be removably supported from a parallel pair of vertical studs of a frame structure.

A further object of the invention is to provide a reusable scaffold jack having no moving parts.

The above and other objects and advantages of the invention will be more readily understood from the following description considered in conjunction with the accompanying drawing, in which:

FIGURE 1 is a perspective view of a scaffold supported on the outer wall of a frame structure in accordance with the invention;

FIGURE 2 is a vertical cross-sectional view of the scaifold of FIGURE 1 taken on line 2-2 thereof;

FIGURE 3 is a perspective view illustrating the upper end support for the scaffold jack of FIGURE 2; and

FIGURE 4 is a perspective view illustrating the lower end support of the scaffold jack.

Referring now to the drawing, and particularly to FIGURE 1, it will be seen that a frame structure A has an outer wall from which a scaffold B is supported by means of several scaffold jacks C, all in accordance with the invention. The outer wall of structure A includes vertically disposed, parallel studs 10, 11, 19. The lower ends of all the studs are supported upon a horizontally extending bottom plate 20. As shown in FIG- URE 1, one of the scaffold jacks C is supported from studs and 11, another from studs and 16, and the remaining scafiold jack from studs 18 and 9.

Scaffold B is seen to include a horizontal walkway comprising a plurality of planks extending parallel to the structure wall. In FIGURE 2 the planks are identified by respective reference numerals 21 26. It will also be seen, in FIGURES 1 and 2, that a lock block 60 is utilized in conjunction with each scaffold jack C, for maintaining the scaffold jack in fixed position relative to the structure wall from which it is supported.

Charles The structure of one of the scatfold jacks C will now be described.

Scaffold jack C includes a horizontally disposed beam 30 having one end 31 inserted between two adjacent studs, such as 10, 11. A cross bar 40 is fastened to end 31 of beam 30, at a right angle thereto, and extends horizontally behind the studs 10, 11. At the front or outward side of the structure Wall a cross piece 45 is fastened to beam 30 at portion 32 thereof. Outer end 35 of beam 30 carries a vertically aligned post support 37.

Cross bar 40 on the ends of its forward edge carries teeth 41, 42, adapted to bite into the rear faces of studs 10, 11. Cross piece 45 is rigidly fastened to beam 30 and is spaced from cross bar 40 a distance more than sufiicient to accommodate the studs therebetween. Cross piece 45 is adapted to firmly engage the lock block 60, when driven in front of the studs for forcing teeth 41, 42, to bite into the rear stud faces.

Each tooth section, such as 41, is preferably formed from a section of flat metal plate, as illustrated, with the teeth provided on one longitudinal edge thereof, and the plate then being securely welded to the upper surface of cross bar 40 to form a row of teeth parallel to the cross bar and which face toward cross piece 45. Each row of teeth 41, 42, is preferably long enough to permit some lateral movement of the scaffold jack, while still engaging the full width of the rear stud face. 'Cross piece 45 includes a flat plate 46 resting upon beam 30, and secured thereto as by welding, and a plate section 47 which is turned upward at a right angle to splate section 46. Assuming that the studs are made of two by-four inch lumber it is convenient to make lock blocks 60 of the same material. Each block 60, like cross bar 40, is of sufficient length to simultaneously engage two adjacent studs, while permitting some lateral adjustment if desired.

A rigid support leg 50 has a foot piece 52 fastened to its lower end, the foot piece in turn being adapted to rest upon the plate 20. Support leg 50 extends upward from plate 20 at an angle of approximately 40 degrees from the vertical, and has its upper end rigidly fastened, as by welding, to portion 34 of the beam 30. A rigid brace 51 has its upper end fastened to beam 30 at 33 while its lower end is rigidly fastened to the midportion of support leg 50, at approximately a right angle thereto.

Foot piece 52 includes a horizontal plate 53 and a vertical plate 54 joined together to form an L-shaped member for engaging the upper surface and outer side wall surface of the plate 20. A sharp spike 55 extends downwardly from the juncture of plates 53, 54, at such an angle as to constitute an extension of support leg 50, and serves to penetrate the plate 20 so as to secure foot piece 52 firmly in position. Post support 37 is preferably a section of hollow steel tubing, welded to the end of beam 30 so as to support a post in vertical position.

The other structural members may be tubing, or solid material, as desired.

The operation of the invention is quite simple. First, the scaffold jack is held in its normal position, with cross bar 40 being on the outer side of two adjacent studs of the structural wall. Then the scaffold jack is rotated slightly about the longitudinal axis of beam 30 so that foot piece 52 swings substantially to one side, and cross bar 40 becomes inclined at a sufiicient angle with respect to the horizontal so that it may be inserted between the two adjacent studs. The scaffold jack is again pivoted back to its normal position, and foot piece 52 is placed upon plate 20 intermediate the two supporting studs, with spike 55 penetrating plate 20 to maintain the position of the foot piece. The weight of the scaffold jack causes the upper portion thereof to swing out- Patented Aug. 22, 1961 .9 Ward which in turn causes teeth 41, 42, to bear upon the rear stud faces. The next step is to insert the lock block 60 between the front stud faces and the vertical face of plate 47 of the cross piece 45. The spacing between cross bar 40 and cross piece 45, and the dimensions of the studs and of lock block 60, are so selected that the lock block must initially be inserted at anangle. Finally, the lock block is hammered or driven down (not shown), so as to force cross piece 45 away from the studs and at the same time force the teeth 41, 42 to bite into the rear stud faces.

In using the invention as illustrated a principal part of the load is applied via support leg 50 to the plate 20. A certain amount of horizontal stress is applied to the studs but this is kept Well within safe limits. The locking action of the lock block and teeth prevents vertical movement of end 31 of the beam 30, hence structural rigidity of the scaffold jack is maintained at all times. Furthermore, the cooperative effect of the locking action, and the structural arrangement of the scaffold planks and scatfold jacks, is such as to inhibit each seatfold jack from exhibiting any substantial tendency to pivot around a vertical axis parallel to the studs from which it is suspended.

While only one form of the invention has been illustrated it is apparent that many modifications may be made if so desired. For example, post support 37 at the outer end of beam 30 may be omitted if desired. Also, the upper end of support leg 50 may be hinged to beam 30, and brace 51 may be hinged at one end and detachable at the other, so that the entire scaifold jack may be collapsed for purposes of transportation. Another modification which may be desired is to omit spike 55 and provide a suitable hole either in plate 53 or in plate 54 through which a nail may be driven to accomplish the same end result. Still another modification is to lengthen cross bar 40 so as to simultaneously engage four or more studs in supporting relationship.

In some applications of the invention it may be desired to provide vertical support of beam 30 by means of legs which rest on the ground, and whose vertical length is adjustable. Foot piece 52 may then be unnecessary. In other applications of the invention it may be desired to support both the upper and lower ends of the scaffold jack direct from the studs, using a fastening meansineluding a crossbar 40 and a cross piece 45 at the bottom as well as at the top.

The invention has been described in considerable detail in order to comply with the patent laws by providing a full public disclosure of at least one of its forms. However, such detailed description is not intended in any way to limit the broad features or principles of the invention, or the scope of patent monopoly to be granted.

What I claim is:

1. In a scaffold jack having a normally horizontally disposed beam, means for supporting one end of said beam between a parallel pair of vertical studs of a frame structure, said means comprising: a crossbar carried on said one end of said beam, adapted to extend behind said studs, and having teeth on each end of its forward edge for engaging the rear faces of said studs; and a cross piece carried on said beam parallel to said crossbar and spaced from said crossbar a distance more than suflicient to accommodate said studs therebetween, said cross piece being adapted to engage a block driven in front of said studs for forcing said teeth to bite into said rear faces thereof;

. 2. A scaffold jack as claimed in claim 1 which further includes a support leg fastened to the outer end portion of said beam and extending downwardly and inwardly therefrom, and a foot piece on the lower end of said support leg adapted to be removably attached intermediate said studs to a horizontal plate on which the lower ends of said studs are supported.

3. A scaffold jack as claimed in claim 2 in which said foot piece includes a length of angle iron having a horizontal portion adapted to rest upon the horizontal upper surface of the plate and a vertical portion adapted to engage the vertical outer surface of the plate, and a spike fastened underneath said angle iron in longitudinal alignment with said support leg and adapted to pierce the plate so as to prevent horizontal movement of said foot piece.

4. A scaffold jack as claimed in claim 1 in which both said crossbar and said cross piece are rigidly affixed to said beam.

References Cited in the file of this patent UNITED STATES PATENTS 

